The present invention relates to a keyboard key switch used in a keyboard in which multiple keys are arrayed as a computer input device. More particularly, the invention relates to a stabilizer mechanism in a mouse key or other key switch.
In graphic display devices, mouse or trackball pointing devices are generally positioned as separate items from the keyboard input device, but in such cases a dedicated space is required for the pointing device, thus increasing the overall graphic display device installation surface area. Recently the use of portable computers such as notebook personal computers has been spreading, with mouses, trackballs, touchpads, joysticks, pointing sticks, etc. being built into keyboard devices.
Many of the key switches used in notebook computers and mouses may be given special shapes. For instance, a pair of key tops arrayed to the left and right on the near side of assembly 2 shown in FIG. 1, have a protruding end projecting in a round form upward from the top of the two left and right ends.
In contrast to key tops with this type of shape, in conventional key switches such as Patent No. JP 2001-014083, a pantograph-type switch pushing mechanism is generally positioned at the center, with an X-shaped part of the pantograph mechanism serving as a stabilizer.
Further, when the switch pushing mechanism alone is insufficient, a first approximately C-shaped stabilizer wire is arrayed along the inner perimeter edge of the keyboard. The stabilizer wire is formed with a hinge mechanism such that if one portion of the key top is depressed, other parts of the key top will be depressed at the same level. However, when the ends of these key tops are pushed, and especially when the upper ends of key tops not reached by the C-shaped wire are pushed, contact may not occur due to insufficient depression of the center portion of the key.
Also, notebook computer users touch keys very quickly with a finger touch, and expect normal operation wherever they hit the key top, that is, even if they have only slightly pushed on the key top edge. A stabilizer mechanism is therefore sought so that large key tops such as mouse keys or odd-shaped key tops will operate smoothly.
In light of the above, the present invention seeks to provide a stabilizer mechanism that will solve the abovementioned problems, and which will be easily attached and of a thin-form structure, and with which a key switch will reliably operate.
In order to achieve the above goal, the present invention has a structure as described in the claims. In the key switch stabilizer mechanism of the present invention a membrane sheet having a contact circuit is arrayed between a base plate and a mounting frame, and equipped with a membrane switch push pressure device which causes the contact circuit contact in the mounting frame to go on and off.
The invention is characterized by comprising a first approximately C-shaped stabilizer wire which is connected to both a key top and a base plate, and is further supported so as to be able to turn with respect to the key top; and a second stabilizer wire having a flat portion connected to the base plate, a bent portion, and another flat portion connected to the key top.
According to this constitution, the first and second stabilizer wires are arrayed on the inner peripheral edge of the key top. Responding to the reaction force of the membrane switch push mechanism, the first stabilizer wire rises upward, supported by the bent feet at both ends of the first stabilizer wire, thus pushing the key top into parallel. At the same time, the protruding edge at the top of the key top is supported by the second stabilizer wire. For this reason, when the key top edge is lightly pushed, the second stabilizer maintains its elasticity and distorts, using the base plate protruding seat, and the fitting edge portion housed within the key top also sinks down, such that the membrane switch push mechanism is pushed. The result is that the membrane switch can be operated.
Therefore with the characteristics of the present invention, touching even very lightly any part of the key top surface, in particular the top end peripheral edge, allows a pushing pressure to be imparted to the first and second wires arrayed within the key top, by means of which a membrane push mechanism operates. When pressure on the key top is released, the first and second stabilizer wires follow the reaction force from the membrane switch push mechanism and rise, opening the switch.
In one embodiment of the present invention, the bent end feet portion of the first stabilizer wire form support points which fit onto the mounting frame fitting points. The wire follows the membrane switch push mechanism reaction force and rises upward, thus maintaining key top flatness. The second stabilizer wire is constituted so as to have a spring force which resists the offset push force against the key top protruding end portion. By this means, it is possible to realize reliable on/off operation in a membrane switch.
Another embodiment is characterized in that the protruding end portion of the key top has an engaging piece which projects from the inside surface. This fitting piece forms a sliding engagement surface between the support portions protruding from the corresponding part of the frame. With this configuration, the key top protruding end portion depresses straight down without tilting, so the second stabilizer wire fitting end portion receives pushing force as a unit with the first stabilizer wire, such that the key switch push mechanism can be pressed without excessive effort.
Yet another embodiment of the present invention is characterized in that a keyboard key switch comprises a pair of mouse keys positioned to the left and right on a base plate; each mouse key has a membrane switch push mechanism built onto the top of the base plate; the first stabilizer wire is housed within the mouse key top, and one end of the second stabilizer wire is fit onto the surface of the attaching flange formed on the side of the base plate, while the other end of the second stabilizer wire is fit into the fitting portion of the key top. As a result, the extension portion of the second stabilizer wire is elongated and spring force can be preserved, and the stabilizer mechanism of the present invention takes full advantage of the mouse key operational performance.